Magnetic nanoparticles and micron-sized composite particles have properties useful for the purpose of magnetic separation of target moieties from a fluid. Their surfaces may be functionalized to make them suitable for use as a target-specific binding surface. As a result of this property, magnetic nanoparticles and micron-sized microbeads have been used in laboratory bench-top systems for the purpose of magnetic separation of target components. In such bench-top systems, functionalized magnetic microbeads are mixed with small volumes of a fluid containing both the target moieties and other species in a container. The mixture is then exposed to a permanent magnet that produces an inhomogeneous magnetic field over the entire volume of the container. This actuates and concentrates the magnetic nanoparticles or microbeads at a predetermined location in the fluid container. The non-actuated materials in the supernatant may be separated off, and a chemical or other agent added to the mixture to cleave the bonds between the target moiety and the magnetic entities, thereby allowing the target components to be separated out and then further purified.
Such a magnetic separation method is not suitable if one wishes to apply the magnetic separation to a large volume of a given fluid. Further, the time required for the Brownian motion-mediated separation process when the container is placed near the magnet may be too long and thereby damage the components in the fluid.
What is needed is a method of accelerating the binding time between functionalized magnetic particles and target moieties.
The present invention addresses these requirements.